Synthetics vs. Biologicals

Biological crop inputs are intended to offer farmers substitutes for commercial fertilizers. They tend to disappoint when expected to perform the same.

The Origin of Fertilizers

Historically, crops were fertilized with animal manure and soils were given rest periods to restock the nutrients extracted from the previous harvest. Ammonium, nitrate, and synthesized ammonia fertilizers were discovered in the early 1900’s, and put into mass production in 1940-50, after World War II popularized nitrogen manufacturing for explosives.

Since then, fertilizer applications on field crops have increased significantly, while soil organic matter and biodiversity have been lost. Attempting to shortcut the restoration of healthy populations of important biological actors like mycorrhizal fungi, some crop input manufacturers now offer single-species soil amendments along and claim they can be used to replace traditional fertilizer.

These products struggle to perform in traditional plot trials because a linear side-by-side comparison fails to reflect the complexity of how plants grow in soils. As in calculus, it is the difference between interacting variables, rather than the absolute levels of individual nutrients/species, that informs the best action to be taken for future productivity.

There’s a learning curve involved in how photosynthesis spurs plant activity sending carbohydrates out through the roots to feed soil biology for solubilizing nutrients into forms that plants can use to grow. After education, the most important tool for enacting a successful input-reduction cropping system is lab measurements.

Soil Testing

Different soil testing labs use different mineral extraction methods that vary the interpretations and recommendations on fertilizer applications, and often skew towards maximizing yield only via the macros (NPK). Lowering fertilizer applications on crops without a corresponding drop in yield relies on a combination of soil micronutrient and biological analysis, coupled with sap/tissue testing at key vegetative and filling stages, which only a small handful of labs worldwide can provide.

For many in the regenerative community, the lack of appropriate soil testing lab technology, capacity and access for farmers makes the whole exercise of soil testing unproductive. Standard extract-and-replace soil testing ends up recommending excessive fertilizer applications to achieve a target yield in coming season: a dangerously misleading profit-killer for grain farms, where fertilizer is often the biggest operating expense.

This is going to be difficult to resolve, and it will impact success for startups building models for measuring, reporting and validating (MRV) improvements in soil health. Rather than measuring soil health - why not measure fertilizer application reduction?

Reducing N Escape Without Sacrificing Yield

There are plant nutrition systems in use today that work really well to increase farm profitability by cutting fertilizer, like foliar nitrogen. Plant sap analysis in the growing crop is compared to prior total-extraction and plant-available soil test results to determine which nutrients to apply and when, as the crop grows.

Applying fertilizer to fields when no crops are growing can disrupt the carbon cycle, resulting in pollution and money wasted. Like tillage, nitrogen applications release a flush of emissions, that in the absence of growing plants has nowhere to go except the atmosphere and surrounding waterways.

By contrast, foliar applications of precise amounts of nutrient cocktails can optimize fertilizer’s efficacy at far-reduced nitrogen application rates. Timed foliar feeding enables the release of nutrients already present in the soil to the plants at key vegetative and fill stages of growth.

Earthworms & Other Biological Actors

It’s hard to fathom that anhydrous ammonia, the gas form of nitrogen fertilizer that is also the cheapest and most toxic, is still available and unregulated. Invented to pound soil flat in the construction of airport tarmac surfaces, anhydrous kills earthworms on impact.

Earthworm counts (the # present in a shovel full of soil) are easy and consistent measures of soil health. Being high up on the chain of soil biology, if earthworms aren’t present, it’s a good indication that all of the lower forms of soil microbiology (nematodes, fungi, bacteria, etc.) have been harmed as well.

Fixing depleted soil biology isn’t as straightforward as applying any one biological product in place of commercial fertilizer, because it’s the ratios that matter, not individual species populations. For example, when the fungal:bacterial ratio is out of line, the soil’s carbon:nitrogen balance will be too.

In conventional agronomy, extract-and-replace fertilizer recommendations are designed to feed the plant the nutrients it needs to grow and fill. Regenerative agroecological approaches aim to feed the soil what it needs to optimize the performance of the plants, and all of the other living species in the ecosystem, supporting symbiotic relationships.